What truly cross-continental train trips still exist?

I'm really fascinated by the Vivek Express right now. From wikipedia:

... the longest running train in India, and 8th longest in the world ... runs a total distance of 4,286 km from Dibrugarh in upper Assam, to Kanyakumari at the southern tip of Indian peninsula via Trivandrum Central ... 82:30 hours (almost 4 days). There are 52 halts spanning across a total of 615 intermediate railway stations

In Australia you have The Ghan crossing the continent north-south (almost 3000km from Adelaide to Darwin), and the Indian Pacific crossing it east-west (4350km from Sydney to Perth).

In the U.S. Amtrak is the only long-distance passenger train operator, and on their site you can see a list of all of their routes. The route that looks closest to meeting your criteria is:

• Southwest Chief -- Runs from Chicago, Illinois to Los Angeles, California, or roughly 2/3 the width of the continent. If you add the Lake Shore Limited route (New York to Chicago), you can cover the entire width of the continent from New York to Los Angeles, with only a single transfer in Chicago.

And some other possibilities:

• Silver Service / Palmetto -- Runs from New York, New York to Miami, Florida, covering the entire east coast of the U.S. (but not extending into Canada, so not truly trans-continental).
• Coast Starlight -- Runs from Seattle, Washington to Los Angeles, California, for a trip across the entire U.S. west coast.

There's a new train line from Moscow to Paris. Although not across the whole of Europe geographically, it is definitely crossing the whole continent geopolitically.

In Europe, there is the Venice Simplon Orient-Express (based on the former famous Orient-Express) with many possible routes, including Paris-Istanbul (once a year).

Definitely not for a backpacker on a budget though.

If you want to cross South America or Africa on the North-South or East-West axes, you will have to cross plenty of countries. This makes it very difficult to find nonstop trains, as train travel between countries is not always obvious.

Regarding Europe the situation is similar. Within a vast majority of countries you have decent rail networks. However, when it comes to traveling between countries, the situation is a bit more complicated.

Nevertheless you have a some interesting options in Europe too. Okay, they are probably not covering the whole North-South or East-West ranges. On the other hand, the bumpy shape of Europe makes this difficult anyway.

• From West to East: There is a daily direct train from Amsterdam to Moscow.
• From North to South: There are direct trains from St. Petersburg to the Black Sea (Sevastopol and Sotchi). These run two or three times a week. If you are ready to accept a train change in St. Petersburg, this route can even be extended beyond the arctic circle.

I know that this is a poor comparison with the Trans-Siberian, but not too bad for European standards ;-)

The Sun Thalys runs during summer and connects Amsterdam (close to the North Sea) with Marseille at the Mediterranean ocean. It only runs during summer and I think it was claimed to be the longest distance direct high-speed line in the world at the time (EDIT this may have been true in 2012 but no longer, as there are now longer services in China). It more or less crosses Europe from coast to coast.

The Panama Canal Railway offers one-seat passenger service across the North American continent, with a travel time of one hour.

It's stretching the definition of "continent" a bit, but it's certainly coast-to-coast: the train between Luleå and Narvik over the Iron Ore Line runs twice a day connecting the coast of the Golf of Bothnia to the fjords of the Norwegian Sea. Further south there is the Central Line connecting Sundsvall with the Norwegian fjords at Trondheim, but in the 2012 timetable there are no direct passenger trains on this one. Of course, Scandinavia is just a peninsula, not a continent.

In addition to the Vladivostok-Moscow train going through the entire Trans-Siberia Railway, there is also the China Railways K3/4 train which goes from Beijing to Moscow through Mongolia. After departing Mongolia, the train enters the Trans-Siberian Railway at Ulan-Ude, Buryatia, Russia, and follows the same route as the Vladivostok-Moscow train.

You can thus (almost) cross Asia southeast to northwest, beginning in Hong Kong (or Hanoi, if you prefer). Take the Z98 train from Hung Hom Station, Hong Kong, and you'll get to Beijing West Station. Then take the aforementioned train to Yekaterinburg (requires a change of stations, but nothing too bad), right to the east of the Ural Mountains, which is the Asia-Europe border. If you prefer to start in Hanoi, take the China Railways train number Z6 at Ga Gia Lim, Hanoi, and you'll arrive in Beijing West Station after 3 days. The soft sleepers (which I recommend; they are pretty nice) on the Hong Kong to Beijing train costs around 950 RMB (~137 USD) per ticket, and if you want something cheaper you could go for the hard sleepers at around 750 RMB (~108 USD). I don't know about the Hanoi to Beijing train, but it can't be much more expensive than this.

Unfortunately, there is no passenger rail transportation in Laos and very limited passenger rail in Cambodia, so you can't go farther south. If you begin in Singapore, you could get as far as at the Thai-Lao border on rails. If you manage to go across Laos and into Vietnam by other means, you'll eventually get to Hanoi, where you could hop on a train to Beijing (and eventually Yekaterinburg).

There are two ways to cross the North American continent from East to West within the United States. You either: take the Cresent Train from New York City, Philadelphia or Atlanta to New Orleans, and continue on the Sunset Limited to Los Angeles; or: take the Lakeshore Limited or the Cardinal from New York City or Washington, DC, then continue on any one of the Empire Builder, the California Zephyr, the Southwest Chief, or the Texas Eagle trains to Los Angeles.

There's also this luxurious Rovos Rail from Cape Town, South Africa to Dar es Salaam, Tanzania. In principle, you should then be able to take a few train trips to get to Alexandria, Egypt on the northern rim of Africa (via Addis Ababa, Aswan, Cairo, etc). In practice, I haven't found viable train route yet.

The Eastern and Oriental Express connects Singapore and Bangkok taking 3 days. Well, it costs 1790€ which is a knockout argument for me and probably many others. You can surely do the same trip much cheaper but you have to change trains in Butterworth and Kuala Lumpur as mentioned on seat61.

Further information on Wikipedia

Several colonial powers had ambitious North-South or East-West projects in Africa but none of them were fully realized, among other reasons because of rivalries between these powers (see Cape to Cairo Railway and related articles on Wikipedia).

Still, there is in fact a railroad going across Southern Africa, coast to coast, starting with Angola's Benguela railway and connecting to the “ligne du Katanga” in Congo and further to Zambia, Zimbabwe, Mozambique, Tanzania and South Africa.

I remember watching a documentary about rail transport in Angola, everything was in a very poor state after the civil war with maybe a handful of old locomotives remaining and damaged tracks. Some work has been done to improve the situation but I don't think there are trains all the way to Congo at this time, let alone reliable passenger services.

On the Congolese side, things are most likely in very poor condition as well but I believe there are trains to Zambia and further to the Indian Ocean coast (in Tanzania or in Mozambique over Zimbabwe). Possibly no passenger service either, certainly no uninterrupted service at the trans-Siberian standard. There is also a railroad from Matadi to Kinshasa but it's only barely operational, with no connections further inland.

Besides, Congo or Angola are really not recommended for tourists, people from my family who come from the region don't want their own children to go there so nothing really useful for travellers at this time but but at least the railroad exists and some day things might get better (hopefully not only for visitors).

A more realistic option could be to travel by rail in South Africa. Of course, it feels a bit like cheating because the distances are smaller but it looks like there are nice trains linking two oceans.